Motion converter mechanism



Oct. 5, 1948. q,- s cc r I 2,450,692

MOTION CONVERTER MECHANISM Filed latch 22, 1943- v v 2 She ets-Sheet 1 jINVENTORS C OLUMBUS R. SACCH/N/ LORA/N N VANDERVOORT vdvl ATTORNEY Oct.5, 1948. c, s ETAL 2,450,692

MOTION CONVERTER MECHANI SM 2 Sheets-Sheet 2 Filed March 22, 1943COLUMBUS A. 5.4cc H/N/ LORA/N N.- VANDERVOORT ATTORNEY Patented Qct. 5,.v I I: I

UNITED PATENTOFFICE I Moms oo vnn'rnn mom -m Columbus Bf Sacchini,Euclid, and-Lorain N. Z Vandervoorh Cleveland, Ohio, assignors to The'Marquette Metal Products Company, Cleve-,

land, Ohio, a corporation of Ohio Application March 22,1943, Serial No.479,912

2- Claims. (01. '14-'10) This invention relates to motion convertersome'when the converter is made of the lighter units, that is:mechanisms for converting uni- .non-magneticmetals as is frequentlynecessary a or v directional rotary motion into alternate rotary whenthe unit is to be used on aircraft.

or reciprocating motion and more particularly to Other general objectsof this invention include such a motion converter unit whichv may be 5the provision 'of a motion converter unit for the made small and compactalthough a-high ratio expurposes and of the above indicated type whichists between the input and output speeds and unit: (a) meets all of theforegoing requirementswhich nevertheless operates athigh efllciencywithout overheating although driven by a high when used, for example, asthe drivlng'means speed prime mover, (b) has a high ratio between forwindow and windshield wiper mechanisms on input and output speeds, (c)is extremely rugged aircraft and other vehicles. although made verysmall in size and capable of The general object of this invention is toprooperating for long periods without attention, (d) vide an improvedmechanism for converting high has .the inputand output shafts in planesat right speed unidirectional motion into relatively slow angles to eachother, (e) is easily adjusted as to speed reciprocating or alternaterotary motion. the relative direction between the. input and out- I Inthe cockpits or control cabins of both miliput shafts withintheseplanes, (1) requires but tar and commercial types of airplanes, 'i'orexthe change of one part to adjust the extent of ample, the available roomfor mounting a motion crank throw, (a) is so arranged that the essentialconverter unit for windshield wiper mechanisms working parts can beeasily and quickly assembled is often very restricted, and consequentlyit is and maintained in proper free working relationnecessary that theunit be very small'and 'comship, and (h) 'inc1udes an improved means forpact. Furthermore, it is essential thatit be 'posconvertingstraight-line reciprocating motion into sible to' vary the extent ofoscillationoi' the wiper alternate rotary motion. blades withoutmaterially changing the construc- More specific objects are to providean improved tion of the motion converter unit in order'to favzr motionconverter unit in which (a) a-speed recilitate mass production and thatprovision be jducin'g gear assembly comprises an-eccentric drivmade foreasily adjusting the angle'o t ere Sing' means for an external gearcooperating with ciprocating power output shaft with "respect "to fanannular internal gear, (b) a speedlreducing the unidirectionallyrotating power inputshaft. annularjgear train drivenfromja highspeedpower In addition, a converter unit suitable for driving input shaftcooperating with a helically threadv the windshield wipers of anairplane must proed power output shaft through a: scotch yoke.

vide adequate power-at relatively slow'speeds in a mechanism todrive theoutput shaft with slow order; to enable the .wip'er'arms to keep movingvspeed alternate rotary motion and (c) a gear steadily underadverse'eonditionsfsuch ascausedyoke constrains an external gearv tomove in a by accumulations of sleet and frost and due toss,circularorbit to-cause slow rotation of a cooperathighslipstre'a'm. g gY I r inginternalgea'r, H; 4 1

In many prior-motion converter units designed Other objects andadvantages of this invention to meet the foregoing r quirements, arevolving willbecomeapparent from the following descripscotch yokemechanism which, in turn, drivesthe 4o lwherein: 1;.

crank pin drives a reciprocating crosshead or tion .of a. preferredform-shown in the drawings,

wiper blade operating shaft through a suitable Fig. =ljis' a moreorfless diagrammatic small means for converting'straightslinereciprocating scale plan view showing'one relative position of motioninto alternate rotary motion;v In these the converter unit of thisinvention with respect known units part, if not all. of the speedreduction toa prime mover and atypical or illustrative airrequiredbetween the prime mover and the crank 45 plane windshield structure;Fig. 2 is a. central pin is obtained by a driving worm and a drivensectional view through the converter unit with I worm wheel. Althoughsuch worm actuated the power take-off or output shaft in'a positioninheat which is generated principally by the inherent high: frictionbetween the wormand worm fromthesi'nalljsurface' area of the unit, andcon sequently'has in'overheating of the rela mechanisms have receivedwideapplication, they displaced from the position indicated in Fig. arenotably inemcient. the losses being manifested ,1; Fi 3a is -a sectionalview taken generally at" .l-ljin 2;"Fig'. 4 is a fragmentary, sectionalI view taken generally at 4-1 in Fig, 3: and Fig. Sis a sectionalassembly view taken generally at Human- 1 j. ;Referring to Fig.1,showing typical relatively convergent portions or two airplanewindshield wheel. The heat cannot bereadily dissipated panels A and 1B,convenient mounting positions for a pair of themotion converter units lof this invention are at the top and near or at the center of thesepanels, respectively, so that the pair of units may be drivenrespectively through flexible torque shafts 2 from a suitable primemover, such as .a small high speed electric motor 3. having a pair ofoppositely extending (e. g. flexible) rotary power shafts.- and therebyoscillatably actuate,

through output drive shafts 5. respectively, a pair of wiper blades 9(one shown) in contact with the windshield panels. A single unit i may,of; course. be used, with appropriate driving means,

as a complete converter installation or more than two converter unitsmay be driven b a common power source. 4

Many of the problems encountered in connection with installations on theorder oi. that indicated in Fig. 1 sufficiently well known in the art soas not to require detailed discussion here, some of which have beenhereinbefore mentioned. For further example, numerous problems arepresented by variations in aircraft construction, it being obviouslydesirable to make the mechanism as universally adaptable to the,different constructions as possible. The relative direction of ingoingand outgoing shafting, ondifferent Jobs, may varynearly through 360".Considerable effective and positive power is required at the wiperblades: and. both from the standpoint of minimizing weight and enablingclearvision as well as from the standpoint of non-interference withother essential apparatus, the equipment must be relatively small andcompact; Electric motors which serve as the prime movers are, mostdesirably, o! small size and consequently are of the high speed type andmust be placed as nearly out of the way as possible. The maximum speedof the wiper blades should help the neighborhood of 200 cycles perminute in order to use relatively small, hence inherently high speed,driving motors considerable reduction in speed must be provided forbetween the motors and the wiper mechanism. Suitable speed reductiongearing must be accommodated within an extremely small space andheretofore. in most cases. suflicient speed reduction has not beenattainable withou deleteriousheating of such, gearing.

The casing or housing of the unit i may com prise a generally hollowbody member 9 and a head body member 9. both preferably formed of castaluminum, or the like, secured in cooperating position at a jointincluding an annular bearing-assembly-retainer i9 and a pairof gasketsii and II' by appropriate means such as cap screws i2 (Figs. 3 and 5)passing through openings 14 equally spaced about the periphery of thehead 9 into complementary tapped sockets IS in the body member 9. Themain function of the head 9 is to support an output shaft assembly II,the output shaft 9 of which imparts its alternate rotary motion to thewiper blade GiFig. 1) attached thereto. "The equally spaced openings i4and cooperating sockets l5, shown as four of each, are

concentric with an eccentric shaft ll forming a:

part'of an annular'spee'd-reducing gear assembly i9 cfontained withinthe body 9 so as to enable thef .head= 9 to be-mounted with respect tothe body} in any one of four nihety-degree-displaced positions withthe-head 9 centered'inrelation to thegear assembly i9 thus enabling theoutput shaft assembly ii to function properly many of the four possibleturned positions of the head 9 with respect to the body 9. Two differentturned positions of the head 9 are illustrated in Figs. 1

- screws '12 may be locked by any suitable means such as a tie wire (notshown) inserted through holes in all of the screw heads as generallyrequired in mechanisms used on aircraft.

In addition to the gear assembly i9 the body member 9 contains an inputshaft assembly I9 which comprises a suitable self-contained antifriction(e. g. needle rollers) bearing assembly 2|! slidably received within anopening 2i in a generally tubular lower extension 22 of the body 9against an annular shoulder 24 formed by a reduced inner portion of theopening 2|. The bearing 29 rotatably supports an input drive shaft 25having a pinion 29 secured on a reduced inner end thereof as by anupsetting operation. An annular spacer or distance piece 29 surroundsthe shaft 25 between the pinion 29 and the bearing 29 and a suitable oilseal assembly 29 engages an outer enlarged end portion 39 of the shaft25 and fits tightly within a counterbored portion of the opening 2i..The enlarged end portion 39 has an axial, non-circular socket 3iadapted to receive a complementary terminal part of one of the flexibletorque shafts 2 or, if the mounting position permits, a similar part ofone of the output shafts of the motor 3.

The oil seal assembly or structure 29 may be forced into proper positionby abutment with a pilot sleeve portion 32 of a connector device 34 ofone of the flexible torque shafts 2 and the sleeve 32 may be secured inposition in the conhector device 34 by a snap ring 35. An outer threadedcollar 36 of the device 34 in which the ring 35 is seated is threaded onthe tubular extension 22 and can turn on the pilot sleeve 32 in themanner of a pipe union nut.

The eccentric shaft ll of the speed-reducing annular gear assembly l9has its opposite collinear or axially aligned end portions rotatablysupported in suitable antifriction bearing assemblies 39 and 39,respectively (e. g. similar to hearing 20) and has a central enlargedeccentric portion 40 riding in contact with the inner rollers of' asuitable antifrictionbearing assembly 4! (e. g. needle rollers), theouter periphery of which assembly (retainer. shell for example) issupported in tight contact with the wall of a central opening in a gearor pinion 42 having external teeth arranged to mesh, in a manner to bedescribed later, with an annular gear 44 having uniformly spacedinternal teeth. The needle bearing roller assemblies 20, 39 and 4i=. areshown only diagrammatically on Fig. 2, for simplicity of illustration;but each assembly preferably comprises a shell-like retainer in whichthe needles are retained for free rolling operation by end flanges ofthe retainer shell, as well understood in the art.

Thebearing assembly 39 occupies a socket 45 in an upper portion of theextension 22 and the bearing assembly 39 occupies a central opening in abearing carrier 46 pressed into a non-tooth portion49 of the annulargear 44. The bearing carrier 46 thus becomes in eflect an integral partof the annular gear 44 which comprises a tube counterbored to receivethe carrier 49 as clearly shown on Fig. 2.

The annular-gear 44 is rotatably supported with respect to the body 9 bya pair of suitable antifriction bearing assemblies Bland 5| (ballbearings as shown) pressed into an elongated shouldered recess 8' in thehousing 8. 'Ilhe bear. ing assemblies 50 and BI preferably are made soas to be capable of absorbing some end thrust, and are spaced apart byan annular distance piece 52, being locked in position by the retainer10. The inner race members of the bearings are pressed over the outerperiphery of the annular gear 44 in shouldered recesses 54 and 55,respectively.

A crank plate 58 may be attached to the bearing carrier 46 as bycountersunk flat-headed screws 58. As thus described and as shown clear.ly in Fig. 2, the annular gear 44, the bearing carrier 46, and the crankplate 56 are arranged to rotate as a unit with respect to the housing 8,and

the eccentric shaft I1 is arranged to rotate both with respect to thehousing 8 and the bearing carrier 46..

The eccentric shaft I1 is rotatably driven from the input drive shaft bymeans of a gear 59 in constant mesh with the pinion 26 and suitablysecured to the shaft I'I between the bearing assembly 38 and theeccentric portion 40. An annular gear yoke 60 between the gear 59 andthe internal gear 42 encircles but clears the bearing assembly 4iperipherally thereof as shown in Figs. 2 and 3, and is slidablysupported at diametrically opposite sides by guide pins SI and 6 I(Figs. 3 and 4) which are screwed into tapped openings in the body 8 andslidably, received within openings in lugs 62 and 64, respectively, ofthe gear yoke 60.

The purpose of the gear yoke 60 is to .prevent rotation of the externalgear 42 to which it is slldably keyed as by diametrically opposedintegral tongue portions 65 extending at right an-.

gles to the openings in the lugs 62 and 64 and received withincomplementary diametrically opposed radial slots 66 in the gear 42(Figs. 3 and 4) By virtue of this tongue and slot connection between theyoke 60 and the gear 42, and the fact that the bearing assembly 4|permits rotation of the shaft ll with respect to the gear 42, the gear42 moves in a circular orbit having a diameter equal to twice theeccentricity of the shaft 11. The eccentricity of the shaft H isindicated in Fig. 3 by the distance between the center C of thecollinear end portions of the shaft i1 and the center 0' of the portion40. Movement of the gear 42 in its orbit drives the gear yoke 80 backand forth on the guide pins BI and SI.

The pinion or gear 421s in constant mesh with the annular gear 44 whichis consequently driven as a result of the translation or revolution ofthe external gear 42 in its orbit. Each time that the external gear 42revolves once in its orbit, the annular internal gear 44 rotates, forexample, a distance of two teeth, i. e. a distance equal to the diameterof the orbit on which the external gear revolves.

A suitable counterbalance 61 may be attached to the eccentric shaft llbetween the eccentric portion 40 and the bearing carrier 46 tocompensate for the centrifugal influences of the portion 40 andassociated eccentric parts when the shaft is driven at fairly highspeed. v

For operatively connecting the annular gear guide pins II "and. II. Thepins pass through openings near opposite ends of the crosshead l0 andalso serve, in a manner to be described, as a securing means for aflanged bushing 12 constituting one journal member for the output driveshaft I. Wear on the pin 68 and .the slot 69 is avoided by theinterdisposition of a bearing block ll having a generally rectangularouter contour, as well known in scotch yoke mechanisms.

A helicaily threaded central opening 10' in the crosshead l4 cooperateswith a helical threaded portion I6 of the shaft 5 to drive the shaftwith an oscillating or alternate rotary motion when the crosshead 10 ismoved to and fro in the direction of extent of the shaft 5 as a resultof the revolution of the crank-pin 8B. The shaft 5 is rotatablysupported in antifriction combined thrust bearingassemblies I! and I8pressed, respectively, into a socket 80 in one end of the head 9. (Fig.5) and into an opening 8i in the opposite end of the head 9. The ends ofthe helically'threaded portion 16 abut respectively against the bearingassemblies 18 and I9 and thus hold the shaft 5 in position.

The output drive shaft 6 extends outside of the head 9 through theflanged bushing or hearing sleeve I2 which is secured to the head 9 byhead portions of the guide pins H and II. For this purpose, the guidepins pass through respective apertures in the bushing 12 and arethreaded into tapped openings in the portion of the head 9 which isshown at the bottom of Fig. 5 and extend respectively into openings 82and 84 in the portion of the head 9, shown at the top respectively.

In order to reduce machining tolerances and to eliminate excessive axialmovement of the shaft 5, shims 85 may be placed between the bushing 12and the head 9. The outer tubular portion of the bushing 12 is adaptedto pass through the windshield frame of a vehicle such as an airplaneand has its outer end threaded as at 12' to receive a retaining nut (notshown) whereby the unit I may be suitably retained in position, theshaft 5 having a splined or fluted portion 86 near its outer threadedend to receive a complementary part of a drive arm head section of thewiper blade driving assembly with which associated.

From the drawings and the foregoing description. it will be seen thatthe unit I has its output drive shaft 5 in a plane normal to the planeof the input drive shaft 25 which is of special advantage in manyinstallations since a minimum of space is thereby required by thecomplete windshield wiping mechanism and the prime mover may beconveniently mounted as in a central position between two converters asshown. v

In operation of the unit I, the motor 3 drives the input drive shaft 25at a high speed which, in turn, drives the eccentric shaft I'l throughthe pinion 28 and external gear 59 at a reduced speed which mayconveniently be one-half of that of the shaft 25. Rotation of the.eccentric shaft I'I causes translatory or orbital movement of theexternal gear or pinion 42 in a circular path such that'each time theeccentric shaft l'l rotates once, the gear 42 completes One revolutionabout its orbit and thereby advances the gear 44 a short distance suchas two or more tooth spaces in reassembly It to the output drivev shaftassembly ii. there is provided a crank pin 68 integral with the crankplate 58 and .extending outwardly therefrom at a point displaced fromthe center of the crank plate into a throat slot 89 fully open at bothends and formed in a crosshead ll slidably supported for to and fromotion as bya pair of spect to the gear 44. The respective pitchdiameters of the gears 42 and 44 may be so selected that a speedreduction of 25 to 1 is obtained therebetween, giving an overall speedreduction from the input shaft 25 to the crank pin 68 equal to 50 .to-1. These named numerical values are Rotation of the internal gear 44causes the crank pin 68 to revolve and move the crosshead 10 to and froon the guide pins H and II. By virtue of the helical thread connectionbetween the crosshead l and the shaft 5, to and fro movement of thecrosshead, I0 causes the shaft 6 to move with analternate rotary motionand thus oscillate the wiper blade 6 or other work performing member, asdesired.

The extent of movement of the wiper blade 6 can be predetermined byselection of the of!- center distance or eccentricity of the pins 63with respect to the center of the crank plate 66. It is thus necessaryonly to change but one part of the complete unit I to alter the extentof wiper blade sweep, thus facilitating mass production economies sincethe units I might be used on different types of planes or other vehiclesrequiring various distances of wiper blade travel.

when assembled for use, the housing comprising the body 8 and head 9 isfilled with a suitable lubricant which is adequately sealed at the onlyhigh speed shaft (25) by the oil seal structure 29. The elongatedbushing 12 may have a similar or appropriate sealing structure (notshown); for example, such an arrangement as disclosed by the applicationof C. R, Sacchini, Serial No. 463,745, filed October 29, 1942, nowPatent No. 2,376,011 issued May 15, 1942.

We claim:

1. In a motion converter, an external gear, a rotatable annular gearoperatively in mesh with and surrounding said external gear, aunidirectionally rotating eccentric shaft drivingly connected to androtatable with respect to said ex'- ternal gear, a non-rotatable yoke,means slidably guiding the yoke for movement transverse to the axis ofthe eccentric shaft, said yoke being slidably connected to the externalgear in a manner to constrain the movement of said external gear againstrotation while enabling movement of the external gear in a circularorbit upon 8. rotation of said eccentric shaft, whereby said annulargear is driven at a relatively slow speed upon rotation of saideccentric shaft.

2. In a motion converter mechanism comprising a housing, a continuouslyrotating driving member, an eccentric crank pin driven by the drivingmember, a crosshead in'the housing driven by said crank pin with a toand fro motion, an output shaft having a high pitch helical drive threadconnection with the crosshead operative to'oscillate the shaft, abearing member for e shaft on the housing, and means connecting theNumber Name Date 306,375 Allen Oct. 14, 1884 367,340 Fleak -1--- July26, 1887 548,861 Barter Oct. 29, 1895 886,938 Brush May 5, 1908 900,631Wilde Oct. 6, 190a 1,333,100 Ruiz Mar. 9, 1920 1,831,903 Chrisman et al.Nov. 17, 1931 1,873,380 Gibson Aug. 23, 1932 2,256,055 Probst Sept. 16,1941 FOREIGN PATENTS Number Country Date 19,254 Australia Sept. 11, 193440 138,519 Germany Feb. 3, 1903 480,963 Great Britain Mar. 2, 1938485,969 Germany -1 Nov. 7, 1929 bearing member to the housing andextending inside the housing and siidably engaging the crosshead in amanner to prevent rotation thereof about the axis of the output shaft.

COLUMBUS R. SACCHINI. LORAIN N. VANDERVOORT.

REFERENCES CITED The following references are of record in the die ofthis patent:

UNITED STATES PATENTS

